{-# LANGUAGE Arrows #-}

module Hasura.RemoteSchema.SchemaCache.Build
  ( buildRemoteSchemas,
    addRemoteSchemaP2Setup,
  )
where

import Control.Arrow.Extended
import Control.Arrow.Interpret
import Data.Aeson
import Data.ByteString.Lazy qualified as BL
import Data.Environment qualified as Env
import Data.HashMap.Strict.Extended qualified as M
import Data.Text.Extended
import Hasura.Base.Error
import Hasura.GraphQL.RemoteServer
import Hasura.Incremental qualified as Inc
import Hasura.Prelude
import Hasura.RQL.DDL.Schema.Cache.Common
import Hasura.RQL.DDL.Schema.Cache.Permission
import Hasura.RQL.Types.Metadata.Object
import Hasura.RQL.Types.Roles
import Hasura.RQL.Types.Roles.Internal (CheckPermission (..))
import Hasura.RQL.Types.SchemaCache
import Hasura.RQL.Types.SchemaCache.Build
import Hasura.RemoteSchema.Metadata
import Hasura.RemoteSchema.SchemaCache.Permission (resolveRoleBasedRemoteSchema)
import Hasura.RemoteSchema.SchemaCache.Types
import Hasura.Session
import Hasura.Tracing qualified as Tracing
import Network.HTTP.Client.Manager (HasHttpManagerM (..))

-- Resolves a user specified `RemoteSchemaMetadata` into information rich `RemoteSchemaCtx`
-- However, given the nature of remote relationships, we cannot fully 'resolve' them, so
-- we resolve of remote relationships as much as possible.
buildRemoteSchemas ::
  ( ArrowChoice arr,
    Inc.ArrowDistribute arr,
    ArrowWriter (Seq (Either InconsistentMetadata MetadataDependency)) arr,
    Inc.ArrowCache m arr,
    MonadIO m,
    HasHttpManagerM m,
    Eq remoteRelationshipDefinition,
    ToJSON remoteRelationshipDefinition,
    MonadError QErr m
  ) =>
  Env.Environment ->
  ( (Inc.Dependency (HashMap RemoteSchemaName Inc.InvalidationKey), OrderedRoles, Maybe (HashMap RemoteSchemaName BL.ByteString)),
    [RemoteSchemaMetadataG remoteRelationshipDefinition]
  )
    `arr` HashMap RemoteSchemaName (PartiallyResolvedRemoteSchemaCtxG remoteRelationshipDefinition, MetadataObject)
buildRemoteSchemas env =
  buildInfoMapPreservingMetadata _rsmName mkRemoteSchemaMetadataObject buildRemoteSchema
  where
    -- We want to cache this call because it fetches the remote schema over
    -- HTTP, and we don’t want to re-run that if the remote schema definition
    -- hasn’t changed.
    buildRemoteSchema = Inc.cache proc ((invalidationKeys, orderedRoles, storedIntrospection), remoteSchema@(RemoteSchemaMetadata name defn _comment permissions relationships)) -> do
      Inc.dependOn -< Inc.selectKeyD name invalidationKeys
      remoteSchemaContextParts <-
        (|
          withRecordInconsistency
            ( liftEitherA <<< bindA
                -< runExceptT
                  case M.lookup name =<< storedIntrospection of
                    Nothing -> noopTrace $ addRemoteSchemaP2Setup env name defn
                    Just rawIntro -> do
                      rsDef <- validateRemoteSchemaDef env defn
                      (ir, rsi) <- stitchRemoteSchema rawIntro name rsDef
                      pure (ir, rawIntro, rsi)
            )
          |) (mkRemoteSchemaMetadataObject remoteSchema)
      case remoteSchemaContextParts of
        Nothing -> returnA -< Nothing
        Just (introspection, rawIntrospection, remoteSchemaInfo) -> do
          -- we then resolve permissions
          resolvedPermissions <- buildRemoteSchemaPermissions -< ((name, introspection, orderedRoles), fmap (name,) permissions)
          -- resolve remote relationships
          let transformedRelationships = relationships <&> \RemoteSchemaTypeRelationships {..} -> PartiallyResolvedRemoteRelationship _rstrsName <$> _rstrsRelationships
              remoteSchemaContext =
                RemoteSchemaCtx
                  { _rscName = name,
                    _rscIntroOriginal = introspection,
                    _rscInfo = remoteSchemaInfo,
                    _rscRawIntrospectionResult = rawIntrospection,
                    _rscPermissions = resolvedPermissions,
                    _rscRemoteRelationships = transformedRelationships
                  }
          returnA -< Just remoteSchemaContext

    -- TODO continue propagating MonadTrace up calls so that we can get tracing
    -- for remote schema introspection. This will require modifying CacheBuild.
    noopTrace = Tracing.runTraceTWithReporter Tracing.noReporter Tracing.sampleNever "buildSchemaCacheRule"

    mkRemoteSchemaMetadataObject remoteSchema =
      MetadataObject (MORemoteSchema (_rsmName remoteSchema)) (toJSON remoteSchema)

-- | Resolves a RemoteSchemaPermission metadata object into a 'GraphQL schema'.
buildRemoteSchemaPermissions ::
  ( ArrowChoice arr,
    Inc.ArrowDistribute arr,
    ArrowWriter (Seq (Either InconsistentMetadata MetadataDependency)) arr,
    ArrowKleisli m arr,
    MonadError QErr m
  ) =>
  -- this ridiculous duplication of [(RemoteSchemaName, RemoteSchemaPermissionMetadata)]
  -- instead of just [RemoteSchemaName] is because buildInfoMap doesn't pass `e` to the
  -- mkMetadataObject function. However, that change is very invasive.
  ((RemoteSchemaName, IntrospectionResult, OrderedRoles), [(RemoteSchemaName, RemoteSchemaPermissionMetadata)]) `arr` M.HashMap RoleName IntrospectionResult
buildRemoteSchemaPermissions = proc ((remoteSchemaName, originalIntrospection, orderedRoles), permissions) -> do
  metadataPermissionsMap <- do
    buildInfoMap (_rspmRole . snd) mkRemoteSchemaPermissionMetadataObject buildRemoteSchemaPermission
      -<
        (originalIntrospection, permissions)
  -- convert to the intermediate form `CheckPermission` whose `Semigroup`
  -- instance is used to combine permissions
  let metadataCheckPermissionsMap = CPDefined <$> metadataPermissionsMap
  allRolesUnresolvedPermissionsMap <-
    bindA
      -<
        foldM
          ( \accumulatedRolePermMap (Role roleName (ParentRoles parentRoles)) -> do
              rolePermission <- onNothing (M.lookup roleName accumulatedRolePermMap) $ do
                parentRolePermissions <-
                  for (toList parentRoles) $ \role ->
                    onNothing (M.lookup role accumulatedRolePermMap) $
                      throw500 $
                        "remote schema permissions: bad ordering of roles, could not find the permission of role: " <>> role
                let combinedPermission = sconcat <$> nonEmpty parentRolePermissions
                pure $ fromMaybe CPUndefined combinedPermission
              pure $ M.insert roleName rolePermission accumulatedRolePermMap
          )
          metadataCheckPermissionsMap
          (_unOrderedRoles orderedRoles)
  -- traverse through `allRolesUnresolvedPermissionsMap` to record any inconsistencies (if exists)
  resolvedPermissions <-
    interpretWriter
      -< for (M.toList allRolesUnresolvedPermissionsMap) \(roleName, checkPermission) -> do
        let inconsistentRoleEntity = InconsistentRemoteSchemaPermission remoteSchemaName
        resolvedCheckPermission <- resolveCheckPermission checkPermission roleName inconsistentRoleEntity
        return (roleName, resolvedCheckPermission)
  returnA -< catMaybes $ M.fromList resolvedPermissions
  where
    buildRemoteSchemaPermission = proc (originalIntrospection, (remoteSchemaName, remoteSchemaPerm)) -> do
      let RemoteSchemaPermissionMetadata roleName defn _ = remoteSchemaPerm
          metadataObject = mkRemoteSchemaPermissionMetadataObject (remoteSchemaName, remoteSchemaPerm)
          schemaObject = SORemoteSchemaPermission remoteSchemaName roleName
          providedSchemaDoc = _rspdSchema defn
          addPermContext err = "in remote schema permission for role " <> roleName <<> ": " <> err
      (|
        withRecordInconsistency
          ( do
              (resolvedSchemaIntrospection, dependency) <-
                liftEitherA <<< bindA
                  -<
                    runExceptT $ modifyErr addPermContext $ resolveRoleBasedRemoteSchema roleName remoteSchemaName originalIntrospection providedSchemaDoc
              recordDependencies -< (metadataObject, schemaObject, pure dependency)
              returnA -< resolvedSchemaIntrospection
          )
        |) metadataObject

    mkRemoteSchemaPermissionMetadataObject ::
      (RemoteSchemaName, RemoteSchemaPermissionMetadata) ->
      MetadataObject
    mkRemoteSchemaPermissionMetadataObject (rsName, (RemoteSchemaPermissionMetadata roleName defn _)) =
      let objectId = MORemoteSchemaPermissions rsName roleName
       in MetadataObject objectId $ toJSON defn

addRemoteSchemaP2Setup ::
  (QErrM m, MonadIO m, HasHttpManagerM m, Tracing.MonadTrace m) =>
  Env.Environment ->
  RemoteSchemaName ->
  RemoteSchemaDef ->
  m (IntrospectionResult, BL.ByteString, RemoteSchemaInfo)
addRemoteSchemaP2Setup env name def = do
  rsi <- validateRemoteSchemaDef env def
  httpMgr <- askHttpManager
  fetchRemoteSchema env httpMgr name rsi